A further subject of the present disclosure is a multi-component packaged unit (kit-of-parts) which comprises the above-mentioned agent in addition to an oxidizing agent preparation.
A further subject is also a method in which the above-described agents or multi-component packaged units are used.
Changing the colour of keratin fibers, in particular hair, is an important field of modern cosmetics. The appearance of the hair can thus be adapted both to current trends and to the individual desire of the individual consumer. What are known as oxidation dyes are used to produce permanent intense colorings having good fastness properties. Such dyes usually contain oxidation dye precursors, or what are known as developer components and coupler components. The developer components form the actual colorants under the influence of oxidizing agents or atmospheric oxygen with one another or with coupling to one or more coupler components. The oxidation dyes are exemplified by intense, excellent, long-lasting colour results. However, for naturally acting dyes, a mixture of a larger number of oxidation dye precursors can be used.
Oxidation dye precursors of the developer type are typically based on the basic structure of p-phenylenediamine, of p-aminophenol, or also on the structure of heterocyclic di- or polyamino compounds. Substances of this type are extremely sensitive to atmospheric oxygen. On account of this high reactivity, the use of developers in the form of their free compound—i.e. for example in the form of the free, non-stabilised p-phenylenediamine—is associated with various disadvantages: The compounds themselves have poor storage stability and quickly react prematurely in particular in solution, and in so doing form undesirable compounds. On account of the premature breakdown, the specified content of oxidation dye precursor can deviate significantly from the actual content in the stored formulation.
In order to avoid these disadvantages, oxidation dye precursors of the developer type are therefore generally not used in the form of their free compounds, but instead in stabilised form. For stabilisation, the oxidation dye precursors are converted into their physiologically acceptable salts, i.e. the amino groups present in the substances are converted—wholly or partially—into ammonium groups and are neutralised by counterions (chlorides, bromides, hydrogen sulfates or also sulfates). If a user wishes to dye their hair in a particularly dark hue, for example a dark brown or black shade, said user will thus use a corresponding dye with a particularly high colorant content. Due to the high content of oxidation dye precursors, the corresponding salt content in these agents is also very high.
Oxidative dyes are usually provided in the form of emulsions. Emulsions however, such as O/W emulsions, often react very sensitively to an increase of their salt content. The risk that an emulsion or a dye will separate and prove unstable under storage is therefore particularly high in the case of hues having a high colorant content. It is often also observed that the viscosity of an emulsion is influenced by the salt content. The coloring cream of a dark shade—in which the content of oxidation precursors in salt form is high accordingly—therefore often has a lower viscosity than an otherwise identical coloring cream of a lighter shade.
The commercial distribution of a certain hairdye brand generally comprises a certain portfolio of shades, from which the user can choose the sought colour. Within this portfolio, the same base cream is usually used for all shades, with different amounts of oxidation dye precursors being used in said base cream depending on the particular shade. The darker is the shade, the higher is the content of oxidation dye precursors and the higher is thus also the salt content in the emulsion. So as to be able to use the same base cream within the portfolio, it is of central importance that this cream has a constant and high stability both with use of low and with use of high colorant concentrations. The viscosity should also not exceed or drop below the specific range within this palette of shades.